Error checking codes are a common technique for detecting accidental changes to computer data, and are used in many modern digital networks and storage devices. Typically, an error checking code comprises a fixed-size data element computed from a block of digital data for the purpose of detecting accidental errors that may have been introduced during transmission or storage. The integrity of the block of digital data can be checked at any later time by recomputing the error checking code and comparing it with the stored one. If the codes do not match, then the block of digital data contains a data error.
Examples of error checking codes include, without limitation, checksums and cyclic redundancy checks (CRC). A checksum algorithm yields a different result with high probability if data has been accidentally corrupted. On the other hand, when checksums match, the data is very likely to be free of accidental errors.